Allow for multiple PKI Style Providers

PKIZ will break the existing check in SimpleCert:

A PKIZ provider would mean that no certs could be issued
with a wider array of PKI style Providers possible in the future
this check is going to break all of them, or require them all
to force changes to this code.
Closes-Bug: 1328201

Change-Id: Ia82822b4997473466bd43a3a956e0f85c09e8aa2
Merge "Allow for multiple PKI Style Providers"